Rolls Royce Corporation (RRC) 250 Series Engines

Engine Compressor Splined Adaptor Couplings

Transport Canada has received Special Airworthiness Information Bulletins (SAIB) NE-04-56, NE-04-57 and NE-04-58 from the Federal Aviation Administration (FAA) advising owners, operators, and repair stations of numerous failures of the subject adaptor couplings.

The reported failures were mostly due to fatigue originating from fretting on the outer diameter of the splined adaptor coupling where it mates with the compressor impeller. The subject couplings are part of the shafting system located between the gas generator turbine and the compressor. Both engine manufacturer parts and FAA approved PMA parts are referenced in the above FAA SAIBs.

Failure of this adaptor coupling results in immediate and total loss of power from the engine.

A review of the Service Difficulty database (USA, Canada &Australia) has revealed a number of previous SDRs submitted on the subject splined adaptors.

Transport Canada highly recommends that operators, AMEs and other responsible persons refer to aforementioned FAA publication SAIB NE-04-56, NE-04-57 and NE-04-58, dated March 24, 2004, in order to determine applicability to their own specific aeronautical products.